Healthy soil is the basis for good growth and an abundant harvest. From time to time you should therefore take measures to improve the quality of your soil. The best tips for soil improvement can be found below.
Your garden soil is not fertile? Surely you have already received a variety of tips: Lime and quartz sand, charcoal, clay and special plants should all help improve the soil. But what garden soil can be improved and how? Let us provide you with an overview of good soil conditioners and explain what really helps each soil type.
How to improve soil quality
If you want to improve a garden soil that is too heavy, light, poor in nutrients or compacted with targeted measures, you are aiming at soil fertility. A fertile soil hosts active soil life that performs aggregation of soil crumbs, decomposes organic matter, releases nutrients and most importantly: builds humus! Humus is a prerequisite for healthy, intact soil life and thus also a prerequisite for soil fertility. For a quick overview, here are some measures you can use to make your soil fertile in the long term.
1. Adding humus
The fastest way to get fertile garden soil is to buy humus and spread it around the garden. For those who find purchasing high-quality topsoil or mature compost too expensive, high-quality potting soils such as our Plantura Potting Composts offer a viable alternative.
2. Build and preserve humus
With proper humus management, you can accumulate humus in your soil. Humus management pays attention to soil pH, soil temperature, tillage and soil nutrient supply to bring humus decomposition and humus buildup into the desired balance. It is based on the incorporation of organic material such as mulch, fertilisers, plant residues, and horse manure. Our Plantura Fertilisers also ensure an increase in the humus content of the soil thanks to the mycorrhiza fungi it contains.
3. Eliminate compaction
Compaction in the soil inhibits plant growth in many ways: On the one hand, fine roots have a lot of resistance to overcome during growth, leaving the entire root system shallower and more susceptible to drought. On the other hand, a lack of oxygen can quickly occur in compacted soils – especially after rainfall, when water cannot drain away easily. Removal of compaction can be done mechanically, for example, by deep digging, raking or milling. To learn how to proceed in loosening the soil, see our special article. For deeper compaction, deep-rooted green manuring will help, and we’ll return to this later.
4. Regulating the pH value
Depending on the type of rock underlying the soil, soils are more or less acidic or alkaline. Humus accumulates on acidic soils, but nutrients are poorly released or unavailable to plants. On alkaline soils, hardly any humus is built up and other nutrients, in turn, cannot be absorbed by plants. Too high pH values can be corrected with the help of bark humus, too low ones are adjusted with lime. A suitable pH value for most plants is between 5.5 and 7.0.
5. Soil improvement through minerals
In addition to organic substances, mineral substances can also be used for soil improvement. We have listed the most important ones for you:
Sand: Sand is one of the coarsest grain sizes in soils. It can be incorporated into very clayey soils to improve permeability and root aeration. In addition, yellow sand brings in iron compounds that can be used by plants as trace nutrients. Up to 50 litres of sand per square metre may be necessary for very heavy soils.
Uses: heavy, clay-rich soils.
Lime: Soil liming is done to increase the soil pH. Calcium carbonate is a slow-acting lime that should only be used on sandy soils. From heavy loam and clay soils, only quicklime, which acts faster, has the desired effect. Incidentally, fertilising with ash or fertilising with eggshells can also adjust the desired pH.
Uses: on acidic soils.
Clay minerals: Clay is the finest grain size in soils. The tiny clay minerals have a very large surface area and store water and nutrients. They cannot do this as well as humus, but in return they are not degraded by microorganisms. Clay can be easily distributed, for example, in the form of granulated bentonite. Sandy soils benefit most from clay, as it improves their water-holding capacity and nutrient retention.
Uses: sandy soils.
Plant charcoal: Plant charcoal is a fairly new soil improver. It is charred, i.e. incompletely burned, organic matter such as wood. In this state, it is also called pyrogenic carbon (from ancient Greek pyr = fire and Latin generare = to produce). This carbon can serve as a starting point for further humus buildup. This makes the application of plant charcoal a good measure for very humus-poor soils that are to be improved with organic fertilisers, mulch or manure.
Uses: humus poor soil.
Primary rock flour: Primary rock flour is finely ground rock. Acidic basalt or alkaline diabase are available commercially. They change the soil pH and also provide slow-release nutrients and trace nutrients. They have particularly great benefits on predominantly organic, anaemic soils. However, the release of nutrients depends heavily on an active soil life and starts after one year at the earliest – and then continues for several years.
Uses: nutrient-poor forest soils, anaemic soils.
Mineral fertiliser: Mineral fertiliser is purely mineral as the name suggests, but it cannot really be called a soil improver. It increases the fertility of a soil for a short time by providing nutrients for plants, but mineral fertilisation alone leads to humus depletion and thus lowers soil fertility in the long term.
Tip: Because the base materials of organic fertilisers are often low in essential potassium, some mineral potassium is added to them. Thus, some of our Plantura Potting Composts also contain a minimal amount of mineral nutrient salts. However, because the lion’s share is purely organic, even this small mineral share does not harm the soil; on the contrary, plants can thus grow healthier – which also benefits the soil.
6. Soil improvement through plants
Planting is a promise of salvation for any type of soil. As a rule of thumb, soil should never be left bare at any time. To improve soil before planting, special green manure plants can be used. They root and loosen the soil, stimulate soil life, dissolve nutrients, contribute to clump formation and protect against erosion and drought. They also suppress weeds. Here, we present a few green manure plants that will increase your soil fertility.
Tip: Many green manure plants are legumes (nitrogen collectors). They live in symbiosis with root bacteria, which fix nitrogen from the air via a special enzyme complex and pass it on to the plant. When a green manure plant is incorporated, it fertilises the soil with nitrogen. Legumes include, for example, peas and lupins.
7. Diverse crop rotation and mixed crops
Peas should not accompany other peas, but garlic and carrots are good bed neighbours. There is much truth in these old wisdoms. If you plant related species too often on the same patch of soil, you will eventually be faced with sickly plants and low yields.
Conclusion: How to improve soil in the garden
The crucial element in improving any garden soil is humus. Because humus is the best and most natural soil improver you can get! You also support healthy soil by avoiding unnecessary chemicals in the garden. That is why we at Plantura rely on primarily organic fertilizers, peat-reduced potting soils and beneficial insect-friendly pesticides, which we offer in our Plantura Shop.